1. Field of the Invention
The present invention relates to a synthesized inorganic ion exchange material and a detergent composition containing the same, and more specifically to a synthesized inorganic ion exchange material excellent in ion exchange capacity, alkaline capacity, and cationic exchange speed, and having anti-solubility in water, and a detergent composition containing such a synthesized inorganic ion exchange material.
2. Discussion of the Related Art
To date, a large number of chelating agents, ion exchange materials, precipitants, dispersants and other substances have been reported to be used for detergent builders. In recent years, the use of tripolyphosphates has decreased, since they can cause eutrophication in closed freshwater areas such as lakes and marshes. Instead, crystalline aluminosilicates, typically those disclosed in Japanese Patent Laid-Open Nos. 50-12381 and 51-12805, have been commonly used.
Although sodium silicate has an ion exchange capacity not less than that of zeolite, its use has been limited since it is soluble in water. As a means for solving this problem, a method in which sodium silicate is thermally dehydrated, baked, and powdered and methods utilizing the obtained product are disclosed in Japanese Patent Laid-Open Nos. 60-239320 and 60-227895 and U.S. Pat. Nos. 4,664,839 and 5,211,930. Also, a method in which part of the silicon of sodium silicate is isomorphously replaced with aluminum in a similar manner is disclosed in Japanese Patent Laid-Open No. 3-93649. However, both methods have problems in that the obtained anti-solubility is insufficient and the ion exchange capacity is low. Also, crystalline calcium silicate alkali hydrates obtained by hydrothermal synthesis are disclosed in Japanese Patent Examined Publication No. 61-59245, but they are substantially unsuitable as detergent builders because of their low ion exchange capacity, though they have sufficient anti-solubility in water. Moreover, because their grain shape is in the form of coarse long fibers or mica, their aqueous dispersibility is low so that the actual ion exchange capacity shows further reduction. Also, DD-279234A1 publication discloses a crystalline magnesium-containing silicate obtained by hydrothermal synthesis, but there is a problem in that this silicate is extremely low in ion exchange capacity, making it impossible to be practically used as a detergent builder.
Japanese Patent Laid-Open No. 5-279013 (corresponding to EP-A-0,550,048) discloses an inorganic ion exchange material having excellent anti-solubility in water and ion exchange capacity which contains an alkaline earth metal. However, this publication does not teach or appreciate the usefulness of high ion exchange speed. An ion exchange material having a high ion exchange speed is able to capture Ca ions in water for washing in a short period of time, so that the ion exchange material serves to aid the action of surfactants. Therefore, it can be suitably used for builders in detergents. Such a high-ion exchange speed silicate has not been conventionally known.
As described above, it has been difficult to obtain an inorganic ion exchange material which is excellent in both ion exchange speed and ion exchange capacity, and the development of such an inorganic ion exchange material having improvements in these properties has been in demand.